Along with the rapid increase of electronic information handled in other organizations, many storage subsystems are introduced and operated in the IT systems of organizations. One of the problems of introducing many storage subsystems in a computer system is that the management costs of administrators managing the computer system are increased. In order to facilitate management of multiple storage subsystems, a storage virtualization technique is used widely to enable multiple storage subsystems to be accessed as a single storage.
One example of virtualization is the virtualization of volumes. The storage subsystem constitutes one or multiple logical volumes from multiple physical devices, and provides the same to a host system such as a host computer using the storage subsystem. Furthermore, another form of virtualization exists where multiple logical volumes provided by the multiple storage subsystems are virtualized as one or multiple virtual volumes, provided to a host system.
According to another virtualization example, there is a proposal to virtualize the whole storage subsystem. For example, Patent Literature 1 discloses an art of providing multiple logical volumes of multiple real storage subsystems as logical volumes within a single virtual storage subsystem to a host computer and a management computer in a computer system where multiple real storage subsystems are mutually connected via a network.